Cartridge fuse and fuse length with heat transfer means



' July 25, 1967 E. JACKS ETAL 3,333,076

CARTRIDGE FUSE AND FUSE LENGTH WITH HEAT TRANSFER MEANS Filed NOV. 50 19651 3,333,676 Patented July 25, 1967 United States Patent 3 333 076 The invention enables fuse-links to be produced which, CARTRIDGE FUSE A FUSE LENGTH WITH at any gigien curren1t,hrukpture at a later tlmeltlhlaincvigoild a HEAT TRANSFER MEANS compara e norma ig -rupture-capacity use- Eric Jacks and John Feenan, Liverpool, England, assignors link in which a filler is interposed between the fuse-eleto The English Electric Company Limited, London, 5 ment and the fuse body, or would a comparable fusefigefi l g zg g ll g gz Ser No 414 598 link in which a uniform fuse-element is uniformly spaced r 9 a from the fuse body. It also enables the time required, Claims priority, application Great Britain, Dec. 5, 1963, at any given Current, before rupture takes place to be easily controlled. A fuse-link embodying the invention 1 Claim. (Cl. 200-131) 10 may thus have a more precise time-current characteris- The invention relates to fuse-links.

According to this invention there is provided a fuse link comprising a tubular ceramic body, defining a cylindrical bore, two metallic end caps secured to and embracing the tie which is advantageous in certain applications.

What we claimas our invention and desire to secure by Letters Patent is:

A fuse link comprising opposite ends of the body to seal the said bore, a single fusible wire substantially circular in cross-section connected to said end caps and extending therebctween substantially centrally within the tubular body, and a plurala ity of cylindrical ceramic discs located within the said bore and making heat-conductive contact with the body over their outer periphery, the beads together defining an aligned bore through which said fusible wire extends and making heat-conductive contact with said fusible wire at a plurality of spaced positions along its length intermediate the said end caps whereby to increase the heat dissipated from said portions relatively to the remaining portions of said fusible wire in response to the passage of current therethrough.

One example of a fuse link embodying this invention will now be described with reference to the accompanying drawing in which the figure shows a sectional elevation of the fuse link.

Referring now to the figure, the fuse link comprises a tubular ceramic body 10 having metallic end caps 11 between which -a fuse element 20 comprising a single wire of circular cross-section, is connected. This fuse element extends through aligned holes in four ceramic discs or beads 50 which are mounted in the fuse body 10. The

15 a tubular ceramic body defining a cylindrical bore,

two metallic end caps secured to and embracing the opposite ends of the body to seal the said bore, single fusible wire substantially circular in crosssection connected to said end caps and extending therebetween substantially centrally within the tubular body, and a plurality of cylindrical ceramic discs disposed along a common axis within the said bore and making heat-conductive contact with the body over their outer periphery, the discs together defining an aligned bore through which said fusible wire extends and making heat-conductive contact with said fusible wire at a plurality of spaced positions along its length, said discs being confined to the central portion of said tubular body intermediate the said end caps whereby to increase the heat dissipated from said portions relatively to the remaining portions of said fusible wire in response to the passage of current therethrough.

References Cited UNITED STATES PATENTS discs are in physical contact with both the fuse body 10 901,261 10/1908' Reynolds et 200135 and with central portions 51 of the fuse-element 20 and 943,698 12/1909 Murray are the means of increasing the heat transfer from the 2,157,905 5/ 1939 Lohausfin 200-131 central fuse-element portions 51. More particularly, it 2302,82) 11/1942 a Llempt 200-113 will be apparent that without these heat-conducting discs 3,116,389 12/1963 Wlthers 200-131 in contact with the central portions of the fuse element 3,179,773 4/ 1965 Keeley 200120 the rate of heat generation there will be much greater 3,194r923 7/ 1965 Camfifon 200-420 tlfian iln tthe rerria'mintg end gorttionssiizlie heat is lost 1flrom FOREIGN PATENTS t ese a ter por lOIlS y con uc ion in e en caps, w ere- 44,957 10/1961 Poland. as by placing such heat conductors 1n contact with these 553,761 6/1943 Great Britain.

central portions the rate of heat loss from the element may be carefully controlled along its length. The discs may be varied in thickness, position, and number to achieve particular characteristics of the fuse.

BERNARD A. GILHEANY, Primary Examiner.

H. B. GILSON, Assistant Examiner. 

